This research project involves the isolation and identification of individual histocompatibility genes in rabbits. We are taking advantage of the availability of four inbred lines of rabbits developed at the Jackson Laboratory. Each line consists of families or sublines which may differ at one or a small number of histocompatibility genes. Such differences will be tested through appropriate breeding techniques in combination with tissue grafting. We then will attempt to develop congenic resistant lines on the basis of test results; followng this, properties of individual histocompatibility genes and antigenic specificities (with respect to tissue transplantation) will be studied. We will investigate male-to-female histoincompatibility, which no current unified theory adequately explains. Our research will also investigate the effect of Hg (erythrocyte antigen) loci on tissue transplantation. As a model for the genetics of histocompatibility, we will examine the rabbit system.